From Fragmentation to Construction—from Void to Massive: Fascination with Organic Mass Spectrometry and the Synthesis of Novel Three‐Dimensional Polycyclic Aromatic Hydrocarbons

Abstract

Detailed insights gained from our research into the gas-phase chemistry of ionized and protonated diphenylalkanes and their congeners, obtained by extended synthesis of isotopically labeled model compounds and mass spectrometry, are presented and merged with those acquired during our development of a new family of polycyclic hydrocarbons, the centropolyindanes. Aside from a Personal Account that describes "two scientific lives in one", it is demonstrated, on the one hand, how our understanding of organic chemistry can help to shed light on the details of mass spectrometric fragmentation and to unravel, in a more fundamental way, the unimolecular reactivity of gaseous ions. On the other hand, it is shown how unexpected reactivity of related ions in solution, being subject to the very same fundamentals of organic chemistry, can lead to the construction of novel and, in part, unique three-dimensional polycyclic structures that may contribute to future research in material science. Two such apparently independent fields of organic chemistry may be seen as joint contributions of the art of science.

Centrohexaindane: six benzene rings mutually fixed in three dimensions – solid-state structure and six-fold nitration

“…In fact, only three isomers are possible under these restrictions, namely, a nonsymmetrical one, 8 (C 1 ), and two C ssymmetrical ones, 9 and 10. Applying again a systematic analysis of the incremental chemical shifts caused by the four nitro groups in these isomeric structures allowed us to assign their structures and to estimate the isomer ratio [8] : [9] : [10] ∼ 2 : 2 : 1. As an example, the isolated ortho-hydrogen atoms H a and H a' at the doubly nitrated benzene ring of 8−10 can be used as an anchor point for unequivocally assigning the three isomeric structures.…”

“…Centrohexaindane has been the first topologically nonplanar hydrocarbon the structure of which corresponds to the complete graph K 5 [5−7] and it represents the largest member of the family of centropolyindanes. [8,9] Triptindane (2), [10] tribenzotriquinacene (TBTQ, 3) [11−13] and all-cis-fenestrindane (4) [14] are the most prominent lower congeners of 1, and their chemistry has been developed since to quite some extent. [8a,12,13,15−32] Since 2, 3 and 4 represent structural cuttings of 1 (in fourfold and, respectively, threefold manner), centrohexaindane can also be regarded as an expanded, multiple [3.3.3]propellane, triquinacene, and fenestrane derivative of 2, 3 and 4, respectively.…”

Synthetic Strategies for the Regioselective Functionalization of Tribenzotriquinacenes

“…8 The history and chemistry of TBTQ and its derivatives have already been summarized in some excellent accounts. 6,9,10 In this short review, we therefore do not intend to give a comprehensive overview of TBTQs in general. In fact, we will briefly summarize the most important structural and geometrical aspects of this class of compounds, followed by an overview over general synthetic strategies for both the TBTQ backbone formation as well as the facile postsynthetic modification at specific positions.…”

A cyclopenta[hi]acephenanthrylene bearing two benzoannelated [3.3.3]propellane units: extension of triptindane chemistry

“…Among the members of the centropolyindane family, [1,2] monofuso-centrotriindane or C 3v -tribenzo [3.3.3]propellane 1 (Figure 1), dubbed "triptindane" by H. W. Thompson on the occasion of its first synthesis in the 1960's, [3,4] has gained increasing attention since we had developed an independent and versatile synthesis in 1991. [5] Besides various arene-substituted derivatives, [6−11] those bearing functional groups at the benzylic methylene positions of 1 proved to be important in various aspects and in particular for the extension of the three-dimensional polycyclic framework.…”

“…[5] Besides various arene-substituted derivatives, [6−11] those bearing functional groups at the benzylic methylene positions of 1 proved to be important in various aspects and in particular for the extension of the three-dimensional polycyclic framework. [1,12−14] Whereas the propellane skeleton of 1 exists in a dynamic equilibrium between two C 3v -symmetrical conformers, [6−8] conversion of the benzylic carbons from sp 3 -into sp 2 -hybridized atomic centers, such as in the monoketone 2 and the triketone 3, [5] gives rise to rigidified, C 3v -symmetrical carbon frameworks. In turn, addition of nucleophiles to 3, in particular, opens an access to a large variety of chiral 9,10,11trisubstituted triptindane derivatives.…”